FAIL-SAFE METHOD FOR UPDATING SYSTEM INFORMATION STORED IN A MEMORY

摘要

66446-488 A method for updating system information in a microcomputer-based system involving the step of writing the first unique word representing the progress of data updating process into one of the duplex memories. The data in one of the duplex memories is updated. The first unique word is rewritten to the second unique word representing termination of data updating process after the data stored in the one of duplex memory has been updated. The first unique word representing the progress of data updating process is written into another one of the duplex memories. The data updating process identical to the data updating process performed in the one duplex memory is done in the other duplex memory. The first unique word is written to the second unique word after the data stored in the other duplex memory has been updated. The invention prevents abnormal restart even if updating is suspended due to problems.